The maximum (Quad READ) frequency in regards to the S25FL128Sxx is 104MHz, provided that VIO = VCC = 2.7V to 3.6V.
The maximum (Quad READ) frequency in regards to the S25FL128Sxx is 66MHz, provided that (VIO = 1.65V to 2.7V, VCC = 2.7V to 3.6V)
Refer to page 52, Table 27. Latency Codes for SDR Enhanced High Performance in the S25FL128Sxx datasheet:
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